Stainless steel flux-cored wire for high-temperature welding environment and preparation method of stainless steel flux-cored wire

Abstract

The invention relates to the field of welding materials, in particular to a stainless steel flux-cored wire for a high-temperature welding environment and a preparation method of the stainless steel flux-cored wire, which are used for solving the problem that the corrosion resistance of a common welding material is obviously influenced in the high-temperature welding environment. The stainless steel flux-cored wire comprises powder and a welding skin, the powder is obtained by mixing cobalt-grafted carbon alloy composite powder, molybdenum powder, ferrochrome powder, manganese powder and the like, the high-temperature stability of the flux-cored wire is improved through the cobalt-grafted carbon composite carbon material, and the high-temperature stability is jointly improved through addition of ferroboron powder, vanadium nitride powder and niobium-zirconium alloy powder; the welding skin is prepared by mixing 18Ni300 maraging steel powder and 0Cr18Ni9 austenite steel powder, so that the heat resistance and the corrosion resistance of the welding wire are improved; when the welding wire is used for welding, the welding wire is decomposed at a high temperature, released gas forms a protective layer, meanwhile, molten powder is mixed with a welding skin to form a high-quality welding seam, and it is ensured that the stable and reliable welding effect can also be obtained in a high-temperature environment.

Description

Technical Field

[0001] This invention relates to the field of welding materials, and more specifically to a stainless steel flux-cored welding wire for high-temperature welding environments and its preparation method. Background Technology

[0002] Currently used welding materials are insufficient to meet the required durability and welding quality in high-temperature welding environments. In particular, corrosion resistance and mechanical properties are significantly affected under high temperature and high stress conditions. To improve the overall performance of welding materials in high-temperature environments, this invention provides a stainless steel flux-cored welding wire suitable for high-temperature welding environments. Compared with traditional solid welding wire, flux-cored welding wire has superior high-temperature stability and corrosion resistance. In particular, its weld formation and metallurgical quality at high temperatures provide better welding results. This stainless steel flux-cored welding wire includes flux powder and welding scale. The flux powder is obtained by mixing cobalt-grafted carbon alloy composite powder, molybdenum powder, ferrochrome powder, manganese powder, titanium dioxide, and marble. The welding scale is made of composite stainless steel material, meeting the welding requirements under extreme high-temperature conditions. Summary of the Invention

[0003] In order to overcome the above-mentioned technical problems, the present invention aims to provide a stainless steel flux-cored welding wire for high-temperature welding environments and its preparation method, which solves the problems of poor durability and poor corrosion resistance of existing welding materials in high-temperature welding environments.

[0004] The objective of this invention can be achieved through the following technical solutions: In a first aspect, the present invention provides a method for preparing a stainless steel flux-cored welding wire for high-temperature welding environments, comprising the following steps: Step 1: Weigh out 40-50 parts of cobalt-grafted carbon alloy composite powder, 10-15 parts of molybdenum powder, 15-18 parts of ferrochrome powder, 8-10 parts of manganese powder, 3-5 parts of titanium dioxide, and 6-8 parts of marble powder by weight. Step 2: Mix cobalt-grafted carbon alloy composite powder, molybdenum powder, ferrochrome powder, manganese powder, titanium dioxide, and marble evenly, and vacuum dry to obtain mixed powder. Step 3: Bend the composite stainless steel welding sheet into a U-shaped groove, fill the U-shaped groove with the mixed powder through the powder feeder, close it into an O-shape through the mold, and form it into a flux-cored welding wire with a diameter of 2.5mm through the wire drawing die.

[0005] Furthermore, the chromium content in the ferrochrome powder mentioned in step one is 55%.

[0006] Furthermore, the filling amount of the mixed powder in step three is 32-35%.

[0007] Furthermore, the thickness of the composite stainless steel mentioned in step three is 0.3-0.4 mm.

[0008] Furthermore, the cobalt-grafted carbon alloy composite powder is prepared by the following steps: Step A1: Add ferroboron powder, vanadium nitride powder, and niobium-zirconium alloy powder to a tumble mill and mix at 20-30 r / min for 5-6 h. Place the mixture into a 50 mL stainless steel ball mill jar with a ball-to-material ratio of 10-20:1. The grinding balls are zirconium oxide. The total volume of the powder and grinding balls should occupy about two-thirds of the volume of the ball mill jar. Seal the ball mill jar and purge it with nitrogen. Ball mill at 300-400 r / min for 5-20 h. Place the ball milled material into a graphite mold and heat it to 800-1000℃ under sintering parameters of 20-30℃ / min and a pressure of 30 MPa. Sinter for 20-30 min to obtain alloy material powder. Step A2: Add multi-walled carbon nanotube powder and polyethylene glycol octylphenyl ether aqueous solution to a single-necked flask, stir magnetically for 10-20 min at a stirring rate of 50-100 r / min, add graphene aqueous solution, ultrasonically disperse for 20-30 min, filter, wash the solid 3 times with deionized water, 3 times with acetone, and 3 times with ethanol, and vacuum dry at 50-60℃ for 12-14 h to obtain carbon composite powder; Step A3: Add carbon composite powder and concentrated nitric acid to a three-necked flask equipped with a reflux condenser and a thermometer, reflux at 80-120℃ for 2-4 hours, wash with deionized water 4-6 times after the reaction, and vacuum dry at 60-80℃ for 10-12 hours to obtain carboxylated carbon composite powder. Step A4: Add carboxylated carbon composite powder and cobalt chloride solution to a single-necked flask, stir magnetically for 20-30 min, add dilute sodium hydroxide solution to adjust pH to 5-7, stir magnetically for 6-8 h, centrifuge after reaction, wash with deionized water 3-5 times, and vacuum dry at 60-80℃ for 10-12 h to obtain cobalt-grafted carbon composite powder. Step A5: Place the alloy material powder and cobalt-grafted carbon composite powder into a tumble polishing machine and mix them at a speed of 30-40 r / min for 3-4 hours to obtain cobalt-grafted carbon alloy composite powder.

[0009] Furthermore, in step A1, the ratio of the amount of ferroboron powder, vanadium nitride powder, and niobium-zirconium alloy powder is 5-10g: 5-10g: 5-10g.

[0010] Furthermore, the boron content in the ferroboron powder mentioned in step A1 is 18%, and the niobium content in the niobium-zirconium alloy powder is 1%.

[0011] Furthermore, in step A2, the ratio of the multi-walled carbon nanotube powder, the polyethylene glycol octylphenyl ether aqueous solution, and the graphene aqueous solution is 2-3g: 300-500mL: 300-500mL.

[0012] Furthermore, the aspect ratio of the multi-walled carbon nanotubes described in step A2 is 1000:1.

[0013] Furthermore, the polyethylene glycol octylphenyl ether aqueous solution mentioned in step A2 is an aqueous solution of polyethylene glycol octylphenyl ether X100 with a mass fraction of 1%.

[0014] Furthermore, the concentration of the graphene aqueous solution in step A2 is 5 mg / mL.

[0015] Furthermore, in step A3, the ratio of carbon composite material to concentrated nitric acid is 5-10g: 250-500mL.

[0016] Furthermore, the mass concentration of the concentrated nitric acid mentioned in step A3 is 15%.

[0017] Furthermore, in step A4, the ratio of carboxylated carbon composite powder, cobalt chloride solution, and dilute sodium hydroxide solution is 2.5-5g: 250-500mL: 10-20mL.

[0018] Furthermore, the molar concentration of the cobalt chloride solution in step A4 is 0.05 mol / mL.

[0019] Furthermore, the molar concentration of the dilute sodium hydroxide solution mentioned in step A4 is 0.5 mol / L.

[0020] Furthermore, in step A5, the ratio of the alloy material powder to the cobalt-grafted carbon composite powder is 10-20g: 10-20g.

[0021] Furthermore, the composite stainless steel weld scale is prepared by the following steps: Step B1: Mix 18Ni300 martensitic aging steel powder and 0Cr18Ni9 austenitic steel powder in a tumbler at a speed of 30-40 r / min for 3-4 h. Then, place the mixture into a 100 mL stainless steel ball mill jar with a ball-to-material ratio of 20-30:1. The grinding balls are zirconium oxide. The total volume of the powder and grinding balls should occupy about two-thirds of the volume of the ball mill jar. Seal the ball mill jar and purge it with nitrogen. Ball mill at a speed of 300-400 r / min for 8-15 h. Place the ball milling material into a graphite mold and heat it to 1000-1100 °C at a heating rate of 100-120 °C / min under a vacuum of 7-9 Pa and a pressure of 50 MPa. Sinter for 5-10 min, and then roll it into shape to obtain the composite stainless steel weld skin.

[0022] Furthermore, in step B1, the ratio of 18Ni300 martensitic aging steel powder to 0Cr18Ni9 austenitic steel powder is 20-30g: 20-30g.

[0023] Secondly, the present invention provides a stainless steel flux-cored welding wire for high-temperature welding environments, wherein the stainless steel flux-cored welding wire is prepared according to the above-described preparation method.

[0024] The beneficial effects of this invention are: This invention involves uniformly mixing cobalt-grafted carbon alloy composite powder, molybdenum powder, ferrochrome powder, manganese powder, titanium dioxide, and marble to obtain a flux powder. A composite stainless steel welding wire is then prepared by mixing 18Ni300 martensitic aging steel powder and 0Cr18Ni9 austenitic steel powder. The composite stainless steel is bent into a U-shaped groove, and the mixed flux powder is filled into the U-shaped groove at a filling amount of 32-35%, closing it into an O-shape and drawing it into a flux-cored welding wire with a diameter of 2.5 mm. The multi-walled carbon nanotube powder and graphene composite in the flux powder of this stainless steel flux-cored welding wire improve high-temperature stability and thermal shock resistance. The introduction of cobalt ions improves heat resistance. The addition of ferroborone powder, vanadium nitride, and niobium-zirconium alloy improves the high-temperature stability and wear resistance of the welding wire. The composite stainless steel enhances the heat resistance and corrosion resistance of the welding wire.

[0025] A carbon composite material is obtained by combining multi-walled carbon nanotube powder with graphene. The carbon composite material is then carboxylated through an oxidation reaction, forming coordination bonds between the carboxyl groups and divalent cobalt ions. Cobalt, ferroboron powder, vanadium nitride powder, and niobium-zirconium alloy powder are grafted onto the surface of the carbon composite material to obtain an alloy powder. This composite carbon material improves the high-temperature stability and thermal shock resistance of the welding wire. Cobalt has good heat resistance, the addition of ferroboron powder improves wear resistance, the addition of vanadium nitride powder improves high-temperature stability, and the addition of niobium-zirconium alloy powder improves heat resistance. A composite stainless steel welding wire, prepared by mixing 18Ni300 maraging steel powder and 0Cr18Ni9 austenitic steel powder, improves the heat resistance and corrosion resistance of the welding wire. This stainless steel flux-cored welding wire exhibits excellent heat resistance and wear resistance, making it suitable for high-temperature welding environments. When the welding wire is heated and melted at high temperatures, the stainless steel provides fluidity, while the alloying elements of the flux core interact with the molten metal pool to form a stable metallurgical reaction, enhancing the corrosion resistance of the weld and ensuring welding quality even at high temperatures. Attached Figure Description

[0026] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0027] Figure 1 This is a schematic diagram of the thermal cycling test of Embodiments 1-3 and Comparative Examples 1-3 of the present invention.

[0028] Figure 2 This is a schematic diagram showing the changes in corrosion rate in Examples 1-3 and Comparative Examples 1-3 of the present invention. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] Example 1: This embodiment describes a method for preparing stainless steel flux-cored welding wire for high-temperature welding environments, comprising the following steps: Step S1: Add 5g of ferroboron (18%B), 5g of vanadium nitride powder, and 5g of niobium-zirconium alloy powder (1%Nb) to a tumble mill and mix for 5 hours at 20r / min. Then, place the mixture into a 50mL stainless steel ball mill jar with a ball-to-material ratio of 10:1. The grinding balls are zirconium oxide. The total volume of the powder and grinding balls should be about two-thirds of the volume of the ball mill jar. Seal the ball mill jar and purge it with nitrogen. Ball mill the mixture for 5 hours at 300r / min. Place the ball milled material into a graphite mold and heat it to 800℃ under sintering parameters of 20℃ / min and 30MPa. Sinter for 20 minutes to obtain alloy material powder. Step S2: Add 2g of multi-walled carbon nanotube powder and 300mL of polyethylene glycol octylphenyl ether aqueous solution to a single-necked flask. Stir magnetically for 10min at a stirring rate of 50r / min. Add 300mL of graphene aqueous solution and ultrasonically disperse for 20min. Filter the mixture. Wash the solid three times with deionized water, three times with acetone, and three times with ethanol. Vacuum dry at 50℃ for 12h to obtain carbon composite powder. Step S3: Add 5g of carbon composite powder and 250mL of concentrated nitric acid to a three-necked flask equipped with a reflux condenser and a thermometer. Reflux at 80℃ for 2h. After the reaction is complete, wash with deionized water 4 times and vacuum dry at 60℃ for 10h to obtain carboxylated carbon composite powder. Step S4: Add 2.5g of carboxylated carbon composite powder and 250mL of cobalt chloride solution to a single-necked flask, stir magnetically for 20min, add 10mL of dilute sodium hydroxide solution to adjust the pH to 5, stir magnetically for 6h, centrifuge after the reaction is complete, wash 3 times with deionized water, and vacuum dry at 60℃ for 10h to obtain cobalt-grafted carbon composite powder. Step S5: Put 10g of alloy material powder and 10g of cobalt-grafted carbon composite powder into a tumble polisher and mix for 3 hours at a speed of 30r / min to obtain cobalt-grafted carbon alloy composite powder. Step S6: 20g of 18Ni300 martensitic aging steel powder and 20g of 0Cr18Ni9 austenitic steel powder are placed in a tumble polisher and mixed at 30r / min for 3h. The powder is then placed into a 100mL stainless steel ball mill jar with a ball-to-material ratio of 20:1. The grinding balls are zirconium oxide. The total volume of the powder and grinding balls is about two-thirds of the volume of the ball mill jar. The ball mill jar is sealed and protected with nitrogen gas. The ball milling is carried out at 300r / min for 8h. The abrasive is then placed in a graphite mold and heated to 1000℃ at a heating rate of 100℃ / min under a vacuum of 7Pa and a pressure of 50MPa. It is sintered for 5min and then rolled to obtain a composite stainless steel weld skin. Step S7: Weigh out 40 parts by weight of cobalt-grafted carbon alloy composite powder, 10 parts by weight of molybdenum powder, 15 parts by weight of ferrochrome powder, 8 parts by weight of manganese powder, 3 parts by weight of titanium dioxide, and 6 parts by weight of marble. Step S8: Mix cobalt-grafted carbon alloy composite powder, molybdenum powder, ferrochrome powder, manganese powder, titanium dioxide, and marble evenly, and vacuum dry to obtain mixed powder. Step S9: Bend the 0.3mm thick composite stainless steel welding sheet into a U-shaped groove, fill the U-shaped groove with the mixed powder through the powder feeder, the filling amount of the mixed powder is 32%, then close it into an O-shape through the mold, and form it into a flux-cored welding wire with a diameter of 2.5mm through the wire drawing die.

[0031] Example 2: This embodiment describes a method for preparing stainless steel flux-cored welding wire for high-temperature welding environments, comprising the following steps: Step S1: Add 7.5g of ferroboron boron powder (18%B), 7.5g of vanadium nitride powder, and 7.5g of niobium zirconium alloy powder (1%Nb) to a tumble polisher and mix at 25r / min for 5.5h. Place the powder into a 50mL stainless steel ball mill jar with a ball-to-material ratio of 15:1. The grinding balls are zirconium oxide. The total volume of the powder and grinding balls occupies about two-thirds of the volume of the ball mill jar. Seal the ball mill jar and purge it with nitrogen. Ball mill at 350r / min for 13h. Place the ball milled material into a graphite mold and heat it to 900℃ under sintering parameters of 25℃ / min and 30MPa pressure. Sinter for 25min to obtain alloy material powder. Step S2: Add 2.5g of multi-walled carbon nanotube powder and 400mL of polyethylene glycol octylphenyl ether aqueous solution to a single-necked flask. Stir magnetically for 15min at a stirring rate of 75r / min. Add 400mL of graphene aqueous solution and ultrasonically disperse for 25min. Filter the mixture. Wash the solid three times with deionized water, three times with acetone, and three times with ethanol. Vacuum dry at 55℃ for 13h to obtain carbon composite powder. Step S3: Add 7.5g of carbon composite powder and 375mL of concentrated nitric acid to a three-necked flask equipped with a reflux condenser and a thermometer. Reflux at 100℃ for 3h. After the reaction is complete, wash with deionized water 5 times and vacuum dry at 70℃ for 11h to obtain carboxylated carbon composite powder. Step S4: Add 3.75g of carboxylated carbon composite powder and 375mL of cobalt chloride solution to a single-necked flask, stir magnetically for 25min, add 15mL of dilute sodium hydroxide solution to adjust the pH to 6, stir magnetically for 7h, centrifuge after the reaction is complete, wash with deionized water 4 times, and vacuum dry at 70℃ for 11h to obtain cobalt-grafted carbon composite powder. Step S5: Place 15g of alloy material powder and 15g of cobalt-grafted carbon composite powder into a tumble polisher and mix at a speed of 35r / min for 3.5h to obtain cobalt-grafted carbon alloy composite powder. Step S6: 25g of 18Ni300 martensitic aging steel powder and 25g of 0Cr18Ni9 austenitic steel powder are placed in a tumbler and mixed at 35r / min for 3.5h. The mixture is then placed in a 100mL stainless steel ball mill jar with a ball-to-material ratio of 25:1. The grinding balls are zirconium oxide. The total volume of the powder and grinding balls is about two-thirds of the volume of the ball mill jar. The ball mill jar is then sealed and protected with nitrogen gas. The mixture is ball milled at 350r / min for 11h. The abrasive material is then placed in a graphite mold and heated to 1050℃ at a heating rate of 110℃ / min under a vacuum of 8Pa and a pressure of 50MPa. The mixture is sintered for 7min and then rolled to obtain a composite stainless steel weld skin. Step S7: Weigh out 45 parts by weight of cobalt-grafted carbon alloy composite powder, 12 parts by weight of molybdenum powder, 17 parts by weight of ferrochrome powder, 9 parts by weight of manganese powder, 4 parts by weight of titanium dioxide, and 7 parts by weight of marble. Step S8: Mix cobalt-grafted carbon alloy composite powder, molybdenum powder, ferrochrome powder, manganese powder, titanium dioxide, and marble evenly, and vacuum dry to obtain mixed powder. Step S9: Bend the 0.35mm thick composite stainless steel welding sheet into a U-shaped groove, fill the U-shaped groove with mixed powder through a powder feeder, the filling amount of mixed powder is 33%, then close it into an O-shape through a mold, and form it into a flux-cored welding wire with a diameter of 2.5mm through a wire drawing die.

[0032] Example 3: This embodiment describes a method for preparing stainless steel flux-cored welding wire for high-temperature welding environments, comprising the following steps: Step S1: Add 10g of ferroboron boron powder (18%B), 10g of vanadium nitride powder, and 10g of niobium-zirconium alloy powder (1%Nb) to a tumble mill and mix at 30r / min for 6 hours. Place the mixture into a 50mL stainless steel ball mill jar with a ball-to-material ratio of 20:1. The grinding balls are zirconium oxide. The total volume of the powder and grinding balls occupies about two-thirds of the volume of the ball mill jar. Seal the ball mill jar and purge it with nitrogen. Ball mill at 400r / min for 20 hours. Place the ball milled material into a graphite mold and heat it to 1000℃ under sintering parameters of 30℃ / min and 30MPa pressure. Sinter for 30 minutes to obtain alloy material powder. Step S2: Add 3g of multi-walled carbon nanotube powder and 500mL of polyethylene glycol octylphenyl ether aqueous solution to a single-necked flask. Stir magnetically for 20min at a stirring rate of 100r / min. Add 500mL of graphene aqueous solution and ultrasonically disperse for 30min. Filter the mixture. Wash the solid three times with deionized water, three times with acetone, and three times with ethanol. Vacuum dry at 60℃ for 14h to obtain carbon composite powder. Step S3: Add 10g of carbon composite powder and 500mL of concentrated nitric acid to a three-necked flask equipped with a reflux condenser and a thermometer. Reflux at 120℃ for 4h. After the reaction is complete, wash with deionized water 6 times and vacuum dry at 80℃ for 12h to obtain carboxylated carbon composite powder. Step S4: Add 5g of carboxylated carbon composite powder and 500mL of cobalt chloride solution to a single-necked flask, stir magnetically for 30min, add 20mL of dilute sodium hydroxide solution to adjust the pH to 7, stir magnetically for 8h, centrifuge after the reaction is complete, wash with deionized water 5 times, and vacuum dry at 80℃ for 12h to obtain cobalt-grafted carbon composite powder. Step S5: Put 20g of alloy material powder and 20g of cobalt-grafted carbon composite powder into a tumble polisher and mix them at a speed of 40r / min for 4h to obtain cobalt-grafted carbon alloy composite powder. Step S6: 30g of 18Ni300 martensitic aging steel powder and 30g of 0Cr18Ni9 austenitic steel powder are placed in a tumble polisher and mixed at 40r / min for 4h. The powder is then placed in a 100mL stainless steel ball mill jar with a ball-to-material ratio of 30:1. The grinding balls are zirconium oxide. The total volume of the powder and grinding balls is about two-thirds of the volume of the ball mill jar. The ball mill jar is sealed and protected with nitrogen gas. The ball milling is carried out at 400r / min for 15h. The abrasive is then placed in a graphite mold and heated to 1100℃ at a heating rate of 120℃ / min under a vacuum of 9Pa and a pressure of 50MPa. The mixture is sintered for 10min and then rolled to obtain a composite stainless steel weld skin. Step S7: Weigh out 50 parts by weight of cobalt-grafted carbon alloy composite powder, 15 parts by weight of molybdenum powder, 18 parts by weight of ferrochrome powder, 10 parts by weight of manganese powder, 5 parts by weight of titanium dioxide, and 8 parts by weight of marble. Step S8: Mix cobalt-grafted carbon alloy composite powder, molybdenum powder, ferrochrome powder, manganese powder, titanium dioxide, and marble evenly, and vacuum dry to obtain mixed powder. Step S9: Bend the 0.4mm thick composite stainless steel welding sheet into a U-shaped groove, fill the U-shaped groove with mixed powder through a powder feeder, the filling amount of mixed powder is 35%, then close it into an O-shape through a mold, and form it into a flux-cored welding wire with a diameter of 2.5mm through a wire drawing die.

[0033] Comparative Example 1: This comparative example illustrates a method for preparing a stainless steel flux-cored welding wire for high-temperature welding environments, comprising the following steps: Step S1: Add 10g of ferroboron boron powder (18%B), 10g of vanadium nitride powder, and 10g of niobium-zirconium alloy powder (1%Nb) to a tumble mill and mix at 30r / min for 6 hours. Place the mixture into a 50mL stainless steel ball mill jar with a ball-to-material ratio of 20:1. The grinding balls are zirconium oxide. The total volume of the powder and grinding balls occupies about two-thirds of the volume of the ball mill jar. Seal the ball mill jar and purge it with nitrogen. Ball mill at 400r / min for 20 hours. Place the ball milled material into a graphite mold and heat it to 1000℃ under sintering parameters of 30℃ / min and 30MPa pressure. Sinter for 30 minutes to obtain alloy material powder. Step S2: Add 3g of multi-walled carbon nanotube powder and 500mL of polyethylene glycol octylphenyl ether aqueous solution to a single-necked flask. Stir magnetically for 20min at a stirring rate of 100r / min. Add 500mL of graphene aqueous solution and ultrasonically disperse for 30min. Filter the mixture. Wash the solid three times with deionized water, three times with acetone, and three times with ethanol. Vacuum dry at 60℃ for 14h to obtain carbon composite powder. Step S3: Put 20g of alloy material powder and 20g of carbon composite powder into a tumble polishing machine and mix them at a speed of 40r / min for 4h to obtain carbon alloy composite powder; Step S4: 30g of 18Ni300 martensitic aging steel powder and 30g of 0Cr18Ni9 austenitic steel powder are placed in a tumble polisher and mixed at 40r / min for 4h. The powder is then placed in a 100mL stainless steel ball mill jar with a ball-to-material ratio of 30:1. The grinding balls are zirconium oxide. The total volume of the powder and grinding balls is about two-thirds of the volume of the ball mill jar. The ball mill jar is sealed and protected with nitrogen gas. The ball milling is carried out at 400r / min for 15h. The abrasive is then placed in a graphite mold and heated to 1100℃ at a heating rate of 120℃ / min under a vacuum of 9Pa and a pressure of 50MPa. The mixture is sintered for 10min and then rolled to obtain a composite stainless steel weld skin. Step S5: Weigh out 50 parts of carbon alloy composite powder, 15 parts of molybdenum powder, 18 parts of ferrochrome powder, 10 parts of manganese powder, 5 parts of titanium dioxide, and 8 parts of marble by weight. Step S6: Mix carbon alloy composite powder, molybdenum powder, ferrochrome powder, manganese powder, titanium dioxide, and marble evenly, and vacuum dry to obtain mixed powder. Step S7: Bend the 0.4mm thick composite stainless steel welding sheet into a U-shaped groove, fill the U-shaped groove with mixed powder through a powder feeder, the filling amount of mixed powder is 35%, then close it into an O-shape through a mold, and form it into a flux-cored welding wire with a diameter of 2.5mm through a wire drawing die.

[0034] Comparative Example 2: This comparative example illustrates a method for preparing a stainless steel flux-cored welding wire for high-temperature welding environments, comprising the following steps: Step S1: Add 10g of ferroboron boron powder (18%B), 10g of vanadium nitride powder, and 10g of niobium-zirconium alloy powder (1%Nb) to a tumble mill and mix at 30r / min for 6 hours. Place the mixture into a 50mL stainless steel ball mill jar with a ball-to-material ratio of 20:1. The grinding balls are zirconium oxide. The total volume of the powder and grinding balls occupies about two-thirds of the volume of the ball mill jar. Seal the ball mill jar and purge it with nitrogen. Ball mill at 400r / min for 20 hours. Place the ball milled material into a graphite mold and heat it to 1000℃ under sintering parameters of 30℃ / min and 30MPa pressure. Sinter for 30 minutes to obtain alloy material powder. Step S2: Add 3g of multi-walled carbon nanotube powder and 500mL of polyethylene glycol octylphenyl ether aqueous solution to a single-necked flask. Stir magnetically for 20min at a stirring rate of 100r / min. Add 500mL of graphene aqueous solution and ultrasonically disperse for 30min. Filter the mixture. Wash the solid three times with deionized water, three times with acetone, and three times with ethanol. Vacuum dry at 60℃ for 14h to obtain carbon composite powder. Step S3: Add 10g of carbon composite powder and 500mL of concentrated nitric acid to a three-necked flask equipped with a reflux condenser and a thermometer. Reflux at 120℃ for 4h. After the reaction is complete, wash with deionized water 6 times and vacuum dry at 80℃ for 12h to obtain carboxylated carbon composite powder. Step S4: Add 5g of carboxylated carbon composite powder and 500mL of cobalt chloride solution to a single-necked flask, stir magnetically for 30min, add 20mL of dilute sodium hydroxide solution to adjust the pH to 7, stir magnetically for 8h, centrifuge after the reaction is complete, wash with deionized water 5 times, and vacuum dry at 80℃ for 12h to obtain cobalt-grafted carbon composite powder. Step S5: Put 20g of alloy material powder and 20g of cobalt-grafted carbon composite powder into a tumble polisher and mix them at a speed of 40r / min for 4h to obtain cobalt-grafted carbon alloy composite powder. Step S6: 30g of 18Ni300 martensitic aging steel powder is placed into a 100mL stainless steel ball mill jar with a ball-to-material ratio of 30:1. The grinding balls are zirconium oxide. The total volume of the powder and grinding balls occupies about two-thirds of the volume of the ball mill jar. The ball mill jar is sealed and protected with nitrogen gas. The ball mill is milled at 400r / min for 15h. The milled material is then placed in a graphite mold and heated to 1100℃ at a heating rate of 120℃ / min under a vacuum of 9Pa and a pressure of 50MPa. It is sintered for 10min and then rolled into shape to obtain a stainless steel weld skin. Step S7: Weigh out 50 parts by weight of cobalt-grafted carbon alloy composite powder, 15 parts by weight of molybdenum powder, 18 parts by weight of ferrochrome powder, 10 parts by weight of manganese powder, 5 parts by weight of titanium dioxide, and 8 parts by weight of marble. Step S8: Mix cobalt-grafted carbon alloy composite powder, molybdenum powder, ferrochrome powder, manganese powder, titanium dioxide, and marble evenly, and vacuum dry to obtain mixed powder. Step S9: Bend the 0.4mm thick stainless steel welding sheet into a U-shaped groove, fill the U-shaped groove with the mixed powder through the powder feeder, the filling amount of the mixed powder is 35%, then close it into an O-shape through the mold, and form it into a flux-cored welding wire with a diameter of 2.5mm through the wire drawing die.

[0035] Comparative Example 3: This comparative example illustrates a method for preparing a stainless steel flux-cored welding wire for high-temperature welding environments, comprising the following steps: Step S1: Add 10g of ferroboron boron powder (18%B), 10g of vanadium nitride powder, and 10g of niobium-zirconium alloy powder (1%Nb) to a tumble mill and mix at 30r / min for 6 hours. Place the mixture into a 50mL stainless steel ball mill jar with a ball-to-material ratio of 20:1. The grinding balls are zirconium oxide. The total volume of the powder and grinding balls occupies about two-thirds of the volume of the ball mill jar. Seal the ball mill jar and purge it with nitrogen. Ball mill at 400r / min for 20 hours. Place the ball milled material into a graphite mold and heat it to 1000℃ under sintering parameters of 30℃ / min and 30MPa pressure. Sinter for 30 minutes to obtain alloy material powder. Step S2: Add 3g of multi-walled carbon nanotube powder and 500mL of polyethylene glycol octylphenyl ether aqueous solution to a single-necked flask. Stir magnetically for 20min at a stirring rate of 100r / min. Add 500mL of graphene aqueous solution and ultrasonically disperse for 30min. Filter the mixture. Wash the solid three times with deionized water, three times with acetone, and three times with ethanol. Vacuum dry at 60℃ for 14h to obtain carbon composite powder. Step S3: Add 10g of carbon composite powder and 500mL of concentrated nitric acid to a three-necked flask equipped with a reflux condenser and a thermometer. Reflux at 120℃ for 4h. After the reaction is complete, wash with deionized water 6 times and vacuum dry at 80℃ for 12h to obtain carboxylated carbon composite powder. Step S4: Add 5g of carboxylated carbon composite powder and 500mL of cobalt chloride solution to a single-necked flask, stir magnetically for 30min, add 20mL of dilute sodium hydroxide solution to adjust the pH to 7, stir magnetically for 8h, centrifuge after the reaction is complete, wash with deionized water 5 times, and vacuum dry at 80℃ for 12h to obtain cobalt-grafted carbon composite powder. Step S5: Put 20g of alloy material powder and 20g of cobalt-grafted carbon composite powder into a tumble polisher and mix them at a speed of 40r / min for 4h to obtain cobalt-grafted carbon alloy composite powder. Step S6: 30g of 0Cr18Ni9 austenitic steel powder is placed into a 100mL stainless steel ball mill jar with a ball-to-powder ratio of 30:1. The grinding balls are zirconium oxide. The total volume of the powder and grinding balls occupies about two-thirds of the volume of the ball mill jar. The ball mill jar is sealed and protected with nitrogen gas. The ball mill is run at 400r / min for 15h. The abrasive is then placed in a graphite mold and heated to 1100℃ at a heating rate of 120℃ / min under a vacuum of 9Pa and a pressure of 50MPa. It is sintered for 10min and then rolled into shape to obtain a stainless steel weld skin. Step S7: Weigh out 50 parts by weight of cobalt-grafted carbon alloy composite powder, 15 parts by weight of molybdenum powder, 18 parts by weight of ferrochrome powder, 10 parts by weight of manganese powder, 5 parts by weight of titanium dioxide, and 8 parts by weight of marble. Step S8: Mix cobalt-grafted carbon alloy composite powder, molybdenum powder, ferrochrome powder, manganese powder, titanium dioxide, and marble evenly, and vacuum dry to obtain mixed powder. Step S9: Bend the 0.4mm thick stainless steel welding sheet into a U-shaped groove, fill the U-shaped groove with the mixed powder through the powder feeder, the filling amount of the mixed powder is 35%, then close it into an O-shape through the mold, and form it into a flux-cored welding wire with a diameter of 2.5mm through the wire drawing die.

[0036] See Figure 1 The welding wires of Examples 1-3 and Comparative Examples 1-3 were welded on a stainless steel test plate with dimensions of 200mm×200mm×3mm under the conditions of welding current of 180-220A, arc voltage of 26-30V, and welding speed of 8-12mm / s. Holes were drilled on the surface of the test plate, thermocouple probes were embedded in the holes, fixed with high-temperature glue, and data were collected. See Figure 2 The welding wires of Examples 1-3 and Comparative Examples 1-3 were welded on a stainless steel test plate with a size of 200mm×200mm×3mm to obtain a weld. The weld was then placed in a 10% sulfuric acid solution for corrosion resistance testing. See Figure 1-2 As shown, based on the comparison between Examples 1-3 and Comparative Examples 1-3, it can be seen that the welding wire with cobalt-grafted carbon alloy composite powder added to the welding flux has excellent high-temperature stability and corrosion resistance.

[0037] Based on the comparison between Example 3 and Comparative Example 1, it can be seen that the welding wire with a composite stainless steel weld bead and cobalt-grafted carbon alloy composite powder added to the welding flux has better high-temperature stability and corrosion resistance than the welding wire with a composite stainless steel weld bead and ordinary carbon alloy composite powder added to the welding flux. This indicates that the welding wire with a composite stainless steel weld bead and cobalt-grafted carbon alloy composite powder added to the welding flux has excellent high-temperature stability and corrosion resistance.

[0038] Based on the comparison between Example 3 and Comparative Example 2, it can be seen that the welding wire with a composite stainless steel weld bead and cobalt-grafted carbon alloy composite powder added to the welding flux has better high-temperature stability and corrosion resistance than the welding wire with a 18Ni300 martensitic aging stainless steel weld bead and cobalt-grafted carbon alloy composite powder added to the welding flux. This indicates that the welding wire with a composite stainless steel weld bead and cobalt-grafted carbon alloy composite powder added to the welding flux has excellent high-temperature stability and corrosion resistance.

[0039] Based on the comparison between Example 3 and Comparative Example 3, it can be seen that the welding wire with a composite stainless steel welding wire and cobalt-grafted carbon alloy composite powder added to the welding flux has better high-temperature stability and corrosion resistance than the welding wire with a 0Cr18Ni9 austenitic steel welding wire and cobalt-grafted carbon alloy composite powder added to the welding flux. This indicates that the welding wire with a composite stainless steel welding wire and cobalt-grafted carbon alloy composite powder added to the welding flux has excellent high-temperature stability and corrosion resistance.

[0040] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0041] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in this application, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing a stainless steel flux-cored welding wire for high-temperature welding environments, characterized in that, Includes the following steps: Step 1: Weigh out 40-50 parts of cobalt-grafted carbon alloy composite powder, 10-15 parts of molybdenum powder, 15-18 parts of ferrochrome powder, 8-10 parts of manganese powder, 3-5 parts of titanium dioxide, and 6-8 parts of marble powder by weight. Step 2: Mix cobalt-grafted carbon alloy composite powder, molybdenum powder, ferrochrome powder, manganese powder, titanium dioxide, and marble evenly, and vacuum dry to obtain mixed powder. Step 3: Bend the composite stainless steel welding sheet into a U-shaped groove, fill the U-shaped groove with the mixed powder through the powder feeder, close it into an O-shape through the mold, and form it into a flux-cored welding wire with a diameter of 2.5mm through the wire drawing die; The cobalt-grafted carbon alloy composite powder is prepared by the following steps: Step A1: Add ferroboron powder, vanadium nitride powder, and niobium-zirconium alloy powder to a tumbler and mix them. Place the mixture into a stainless steel ball mill jar. The grinding balls are zirconium oxide. The total volume of the powder and grinding balls is about two-thirds of the volume of the ball mill jar. Seal the ball mill jar and ball mill under nitrogen protection. Place the abrasive balls into a graphite mold and heat to sinter to obtain alloy material powder. Step A2: Magnetically stir the multi-walled carbon nanotube powder and polyethylene glycol octylphenyl ether aqueous solution, add graphene aqueous solution and ultrasonically disperse, filter, wash the solid with deionized water, wash with acetone, wash with ethanol, and vacuum dry to obtain carbon composite powder; Step A3: Add carbon composite powder and concentrated nitric acid to a three-necked flask and reflux. After the reaction is complete, wash with deionized water and dry under vacuum to obtain carboxylated carbon composite powder. Step A4: Stir the carboxylated carbon composite powder and cobalt chloride solution magnetically, add dilute sodium hydroxide solution to adjust the pH, stir magnetically, centrifuge after the reaction is complete, wash with deionized water, and vacuum dry to obtain cobalt-grafted carbon composite powder. Step A5: Mix the alloy material powder and cobalt-grafted carbon composite powder in a tumble polishing machine to obtain cobalt-grafted carbon alloy composite powder.

2. The method for preparing a stainless steel flux-cored welding wire for high-temperature welding environments according to claim 1, characterized in that, The stainless steel flux-cored welding wire comprises a mixed flux powder and a composite stainless steel welding sheet; The chromium content in the ferrochrome powder is 55%; The filling amount of the mixed powder is 32-35%; The thickness of the composite stainless steel is 0.3-0.4 mm.

3. The method for preparing a stainless steel flux-cored welding wire for high-temperature welding environments according to claim 1, characterized in that, In step A1, the ratio of ferroboron powder, vanadium nitride powder, and niobium-zirconium alloy powder is 5-10g:5-10g:5-10g; the ferroboron powder contains 18% boron, and the niobium alloy powder contains 1% niobium.

4. The method for preparing a stainless steel flux-cored welding wire for high-temperature welding environments according to claim 1, characterized in that, In step A2, the ratio of the multi-walled carbon nanotube powder, the polyethylene glycol octylphenyl ether aqueous solution, and the graphene aqueous solution is 2-3g:300-500mL:300-500mL; the aspect ratio of the multi-walled carbon nanotubes is 1000:1; the polyethylene glycol octylphenyl ether aqueous solution is an aqueous solution of 1% polyethylene glycol octylphenyl ether X100 by mass; and the concentration of the graphene aqueous solution is 5mg / mL.

5. The method for preparing a stainless steel flux-cored welding wire for high-temperature welding environments according to claim 1, characterized in that, In step A3, the ratio of carbon composite material to concentrated nitric acid is 5-10g: 250-500mL; the concentration of the concentrated nitric acid is 15%.

6. The method for preparing a stainless steel flux-cored welding wire for high-temperature welding environments according to claim 1, characterized in that, In step A4, the ratio of carboxylated carbon composite powder, cobalt chloride solution, and dilute sodium hydroxide solution is 2.5-5g: 250-500mL: 10-20mL; the concentration of the cobalt chloride solution is 0.05mol / mL; and the concentration of the dilute sodium hydroxide solution is 0.5mol / L.

7. The method for preparing a stainless steel flux-cored welding wire for high-temperature welding environments according to claim 1, characterized in that, The ratio of alloy material powder to cobalt-grafted carbon composite powder in step A5 is 10-20g: 10-20g.

8. The method for preparing a stainless steel flux-cored welding wire for high-temperature welding environments according to claim 1, characterized in that, The composite stainless steel weld scale is prepared by the following steps: Step B1: Mix 18Ni300 martensitic aging steel powder and 0Cr18Ni9 austenitic steel powder in a tumbling mill, then place them in a stainless steel ball mill jar. The grinding balls are zirconium oxide. The total volume of the powder and grinding balls occupies about two-thirds of the volume of the ball mill jar. Seal the ball mill jar and ball mill under nitrogen protection. Place the abrasive balls into a graphite mold and heat to sinter. Then roll them into shape to obtain a composite stainless steel weld skin.

9. A method for preparing a stainless steel flux-cored welding wire for high-temperature welding environments according to claim 8, characterized in that, In step B1, the ratio of 18Ni300 martensitic aging steel powder to 0Cr18Ni9 austenitic steel powder is 20-30g: 20-30g.

10. A stainless steel flux-cored welding wire for high-temperature welding environments, characterized in that, The stainless steel flux-cored welding wire for high-temperature welding environments is prepared by the method described in any one of claims 1-9.

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